The invention relates to a drive system, wherein the drive system has at least two inverters and at least two motors. The invention further relates to a method for the redundancy principle of a drive system.
In electrical drive technology, motors are used both to drive machines and also to accelerate or decelerate vehicles. In this case, the motors are supplied with energy by means of power electronics actuators. This power electronics system is used in closed-loop control or open-loop control as an actuator for the transmission of energy from the energy supply system to the motors. Inverters are used as power electronics actuators for three-phase motors, such as a synchronous motors or an asynchronous motor. In the process, one inverter is used for each motor in many fields of application. This has the advantage that, when there are a plurality of motors, each of said motors can be individually subjected to closed-loop control in respect of torque. In another more cost-effective variant, a plurality of motors, for example two or four, are supplied by one inverter. The costs of the drive system can be reduced owing to this arrangement, which is also called a group drive. However, individual closed-loop control of the motors in respect of torque distribution between the connected motors is no longer possible with this arrangement. At the same time, failure of an inverter then has an effect on all of the motors which are supplied by it, so that said motors can no longer contribute to the drive task. The ability to further maintain operation even in the event of failure of a drive component is called redundancy. Analogously, operation in the event of failure of a drive component is known as redundant operation. Even in the case of an arrangement in which a motor is supplied by in each case one inverter, it has proven disadvantageous when an inverter fails. This has the result that even the motor in question can no longer deliver torque.
In order to prevent the failure of an entire motor, motors with two winding systems are used. In this case, each of the two winding systems is fed by a separate inverter. In the event of failure of an inverter, only some of the torque which can be delivered by the motor is now lost. One disadvantage of this arrangement is the increased costs which arise owing to the additional winding system. At the same time, higher costs are also created owing to the higher number of inverters in comparison to the group drive.